Пошаговое объяснение:
3/8+7/8 = (3+7)/8 = 10/8 = 1 2/8 = 2 1/4;
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6/11+8/11 = (6+8)/11 = 14/11 = 1 3/11;
2/3+2/3 = (2+2)/3 = 4/3 = 1 1/3;
11/12+7/12 = (11+7)/12 = 18/12 = 1 6/12 = 1 1/2.
